This invention relates to a spray device for dispensing liquid products such as paint. It uses a pressurized propellant passing through a spray head to draw a liquid out of its non-pressurized container and atomize it.
Paints have commonly been marketed in single aerosol containers with a volatile propellant. These spray containers permit a uniform application of paint for relatively small jobs where one color is required. Repainting of appliances such as refrigerators, washers and dryers are typical applications where a single aerosol container is useful.
There are many applications, however, where only a small quantity of paint of any given color is required. Examples of such uses are touch-ups to automobile or truck surfaces. The small quantity of the required paint for such applications makes the use of aerosol containers containing the propellant and the paint cost-prohibitive. Such aerosol containers normally include the container, a non-reusable aerosol head, paint propellant and all of the labor and capital costs to assemble it. Largely as a result of the appurtenant costs of a single aerosol container, alternate designs have evolved. In one alternate, the propellant and the paint are held in separate containers and connected by a detachable spray head. In this way, small quantities of paint of different colors may be used with a single container of propellant. Many other liquids, such as lubricants and cosmetics, can also be sprayed with such a device. The discussion relative to paints should be understood to apply to any liquid.
Because of the very nature of detachable containers and a spray head, there are some particularly desirable characteristics. Ideally, a spray head should be readily attachable and detachable to both containers. However, the spray head attachment means should have a mechanism which does not accidentally detach from the containers in use and functions with a standard aerosol can. Prior devices have had some of these desirable characteristics, but have had some shortcomings.
U.S. Pat. No. 3,044,713, which is hereby incorporated by reference, shows one type of spray head. It includes a first section which attaches to a standard aerosol can, a second section which is threaded to a liquid container, and a bridge connecting the two sections. The first section fits over a dome at the top of the aerosol container and generally conforms to its shape. While the disclosed spray head functions reasonably well, it is susceptible to accidental detachment from the aerosol container. In particular, if the paint container were pressed against the aerosol can, the first section of the head would partially dislodge from its correct location on the dome. The misalignment of the spray head with its actuator from the aerosol container will cause a malfunction.
U.S. Pat. No. 3,162,370 to Moonan et al., the disclosure of which is hereby incorporated by reference, also shows a spray head connecting an aerosol can with a container of liquid. The spray head has a first section which fits over the dome of the aerosol can and a small cylindrical portion that fits over the valve stem. Because of the spray head's direct contact with the valve stem, they are susceptible to damage from each other if they are not aligned and attached correctly. Moreover, the spray head does not grip the aerosol can and, accordingly, it may be accidentally misaligned or dislodged.